One of the more critical objectives for the Celtics this season was to allow rookie Kelly Olynyk plenty of opportunity to grow and develop, considering he could become one of the team’s cornerstones. That process will be derailed for a while as coach Brad Stevens said Olynyk could miss “a couple of weeks” with a sprained right ankle.

Olynyk, who had started six of the past eight games, was injured in a collision with Indiana’s Luis Scola during the first half of Boston’s 97-82 loss on Friday. Olynyk was ruled out for the rest of the game and was using crutches afterward. He did not make the trip with the Celtics to Atlanta for Saturday night’s game and Stevens said he won’t be back soon.

“The last I heard was it will be whatever a typical sprained ankle recovery is, a couple of weeks,” Stevens said. “Maybe there is [an upside] down the road.

“He had a little bit of a hamstring that he was dealing with, too. That scares me more because that can become a lingering thing. So sometimes it’s a blessing in disguise when you roll an ankle. Let’s hope that’s the case in Kelly’s situation.”

Against the Hawks, Stevens went with Brandon Bass at power forward and moved Jared Sullinger to center against Al Horford. Sullinger was battling flu-like symptoms Friday, but was healthy enough to go Saturday night. He played 32:32, scored 15 points and grabbed a team-high nine rebounds.

“I was exhausted today, especially playing a back-to-back and being sick,” he said after the Celtics’ 94-87 win over Atlanta. “I just fought through it and it’s my job, can’t have no sick days around here.”

Another reunion

Stevens had a nice pregame chat with former Butler guard Shelvin Mack on the Philips Arena court before the game. Mack played for Stevens at Butler before entering the NBA draft following his junior season in 2011. He was the first Stevens-bred player to stick in the NBA.

Mack, now with his third team, went into Saturday night averaging 4.9 points and 3.1 assists in 14.6 minutes per game.

“Shelvin’s a wonderful person,’’ Stevens said. “I couldn’t be happier, not only for the fact that he’s doing as well as he’s doing, but this is a great program for him. It fits well and I’m really happy for him.

“He’s a guy that, when you recruited him and you would have told me he left in three years to go to the NBA, I would have said that’s probably not the case. He proves everybody wrong all the time and the ride he put us on, particularly his junior year when he took us to the Final Four, was remarkable.”

The road back

Atlanta’s Lou Williams returned to action Nov. 15 after Feb. 7 surgery to repair a torn right anterior cruciate ligament. He underwent surgery just six days prior to the Celtics’ Rajon Rondo and, while all timetables are different, it could be an indication that Rondo is nearing a return.

Williams played 16 minutes in his return, took a two-game break, and then returned Wednesday to play 14:39
against the Pistons. He did not play Friday in a rematch. Williams said his recovery was time-consuming.

“For me, it was just my actual knee being able to function,” Williams said about the most difficult aspect of his rehabilitation. “I really didn’t have a lot of mental issues with it because I always just prepared myself after injuries just to play through it. For me, it was if my knee could function. It just felt good just to be back out there after 10 months.”

The Hawks are being cautious. Williams made his third appearance of the season Saturday, checking in with 2:59 left in the first quarter. He played 17:40, hitting 2 of 7 shots and scoring 6 points.

“We don’t want to try to do too much too early,” he said. “Just as a precaution, we’re not playing a ton of minutes, just to take sure everything is 100 percent.”

Tough times

Sullinger was assessed a Flagrant 1 foul for his chest bump of DeMarre Carroll on his breakaway layup with 6:14 left in the third. Horford had words for Sullinger and then Carroll attempted to approach him. “I went for the ball. It was a hard basketball play. I didn’t try to hurt him,” he said . . . Hawks shooting guard Kyle Korver extended his streak with a successful 3-pointer to 87 two minutes into the first quarter. He moved two short of the NBA record set by former Celtic and BC standout Dana Barros, who began his streak with the 76ers and ended it with the Celtics in 1996
. . . Former All-Star and No. 1 overall pick Elton Brand was on the Hawks’ inactive list but is healthy. He signed a one-year, $4 million deal in the offseason but has played more than 12 minutes in a game just twice this season and has not scored since Nov. 15. . . . Keith Bogans (illness) did not make the trip to Atlanta and is not expected to play Monday in Charlotte. Bogans, acquired in the blockbuster deal with the Nets, has played in just two games this season for a total of 15 minutes.